1. Field of the Invention
The present invention relates to power management in a rack-mountable server chassis.
2. Background of the Related Art
A datacenter is a facility having one or more racks of computer equipment housed in a computer room for convenient access by datacenter personnel. The computer room provides a controlled environment and infrastructure conducive to operating the computer equipment. For example, a computer room may provide electrical utilities with the capacity to power a large volume of rack-mounted computer equipment, and a cooling system capable of removing the correspondingly large quantity of heat generated by the rack-mounted computer equipment. The cooling system in many installations will include a particular arrangement of equipment racks into alternating hot aisles and cold aisles, and a computer room air conditioner (“CRAC”) capable of maintaining a room temperature well below the temperature limits of the computer equipment.
Each rack may support one or more equipment chassis in a stacked relationship. For example, a rack mountable multi-server chassis typically includes multiple server bays having standardized dimensions, so that each server bay can receive a server of corresponding size. The server bays may be closely spaced and aligned to consolidate the servers in a compact, high-density arrangement. A multi-server chassis will also typically include support modules providing shared resources to the servers, such as a power module providing electrical power to the servers, a blower module for moving air through the servers, a network module providing network connectivity to the servers, and a supervisory controller for managing power and other chassis resources. Using support modules to provide shared resources allows the individual servers and the chassis receiving the servers to be made even smaller and more compact.
Servers are typically hot pluggable, so that each server may be individually inserted into a respective bay without significant interruption to any other servers already installed and operating within the multi-server chassis. When a server is inserted into a server bay of the chassis, connectors on the back of the server may mate with corresponding connectors on a midplane or backplane within the chassis, providing electrical power to the server and network connectivity between the server and other servers and equipment. A server may also boot when inserted into a bay. As the server boots, the server may gather information about its own onboard resources, such as hardware and software. When this process is complete, the server may request an amount of power permission from the supervisory controller. The length of time it takes for a server to fully boot, and to subsequently request power permission from a supervisory controller, can be considerable. In some systems, this process of generating an inventory may take more than a minute to complete.